Labels may be attached to items e.g. in order to visually show information associated with the item. The information may comprise e.g. trademark of a manufacturer, advertising information, price information, or operating instructions.
There are a number of label decoration technologies available, each possessing various advantages and challenges. Self-adhesive or pressure-sensitive labels are well-known and widely used in the industry. They suffer however from a number of disadvantages which include the fact that the production process is rather complex and in some cases waste material unnecessarily burdening the environment is created.
Referring to FIG. 1, a known label 100 comprises a carrier layer 10, an adhesive layer 20, and a removable release liner 99. The carrier layer 10 may comprise printed patterns 30.
Traditionally, a release liner is first coated on one side with a release agent, typically silicone, and this release layer is cured with heat. Then on top of this cured silicone layer a layer of pressure-sensitive permanently tacky adhesive is formed. This adhesive layer is typically formed by applying a water based adhesive dispersion on the release layer and then using heat to dry to the dispersion to become a pressure sensitive adhesive film. A paper or filmic print-carrier, face stock, is then laminated to the adhesive coated release liner, at which point the adhesive preferentially transfers to this print carrier. Rolls of such a pressure-sensitive laminate can then be supplied to the next party in the value chain, the printers, who print the face-side of the laminate and die-cut out the labels to the required shape and remove the waste matrix, the unused parts of the face side.
The printed label laminate can then be forwarded in the value chain onwards, and the following party responsible of the end use applies the labels to the items or containers requiring labelling. At this phase the release liner becomes a waste product which is a major disposal issue for users of such labels and the industry at large as well as the whole environment.
An alternative where the use of release liner can be avoided, is the use of wet-glue labels where the pre-printed and die-cut paper labels are coated with a wet-adhesive and then applied directly to the item to be labelled. Typically, such wet-glue label operations are rather messy with a large amount of time being lost for clean-up, set-up and changing of label formats. In addition such wet-glue labels almost always exhibit the unsightly gripper marks of the “label-box” on the finished labelled object. Furthermore wet-glue labels are not available with clear films due to the technical problem that the water cannot satisfactorily evaporate and escape from below the labels, always resulting in unsightly bubbles in the label.
Another decoration technology is that of shrink-sleeves, in which case the total applied cost is very high and the production process very complex. Shrink-sleeve films are normally printed on wide-web gravure or flexographic presses based on such inks, which could cause environmental and safety hazards. After printing, in a separate offline process the film is formed into a tube and the seams adhered together by the use of a solvent welding process. This tube is then cut into shorter lengths, dropped over the article to be labelled and fed through a shrink-tunnel at high temperature causing the film to shrink and fit the shape of the container. Although this technology has produced a number of eye-catching and appealing results for some target market segments, it has a number of disadvantages. These include the fact that by definition a shrink-sleeve covers the whole surface of the object to be labelled and therefore 180° decoration or a label covering only part of the container surface is not possible. The visibility of unsightly seams on shrink-sleeve labels is also negative issue. It is not in practice possible to use shrink-sleeves for containers with flat sides or with containers with handles.
Further, it is not possible to use paper labels with shrink-sleeves nor is it possible to have a variety of textures or tactile effects. It is also not possible to have spot labels, multiple labels on a container or unique label shapes when using shrink-sleeves. It is also not possible to achieve the so-called “No-label” look with shrink-sleeves, that is, it is not possible to have the label blend into the container colour and material as if the label was not there and that the container was pre-printed.
Still another widely-used label technology is that of wrap-around labels. Wrap-around labels can be produced from either paper or film and can be fed from stationary magazines or fed directly from reels. Typically a hot-melt adhesive is applied to the leading edge of the label which is tightly wrapped around the container being rotated at a controlled speed, with the trailing edge being fixed in place by a second narrow strip of hot-melt adhesive. The major markets for such labels are soft drinks and mineral waters due to the lack of premium look and therefore marketing appeal of the labels. It is not possible in this case to achieve the “No-label” look. The choice of materials is very limited and design variety is restricted to that of simple cylindrical shapes.